1. Field of the Invention
The present invention relates to a classification tree based information retrieval scheme which manages a classification tree of information and retrieval information of a plurality of information sources and carries out a retrieval with respect to a plurality of information sources such as databases by tracing entries stored in the classification tree of information.
2. Description of the Background Art
As a conventional classification based information retrieval, a URL retrieval system or a database retrieval system has been realized by classifying information provided at a WWW server or data stored in a database by using a hierarchical structure, and retrieving URL or data by specifying this classified information.
However, in such a conventional retrieval system, a classification tree has been produced for each retrieval system separately, so that the retrieval system and the classification tree, data and the classification tree, and the system and data have been inseparably defined.
A conventional classification tree based information retrieval system has been associated with the following problems.
(1) A classification tree produced in some retrieval system is constructed according to the data classification method and the database retrieval factors of that retrieval system so that it has been difficult to re-utilize this classification tree in other retrieval systems.
(2) In the case of changing a classification of data with respect to data already registered in a database, it has been necessary to change one or both of the classification of data stored in the database and the location information of these data that is managed by the classification tree, so that the change of the classification has not been easy.
(3) The retrieval items and the retrieval conditions are inseparably defined with the classification tree, so that there is no flexibility in the retrieval method.
Also, the conventional classification tree based URL retrieval system has been associated with the following problems.
(4) The URLs that are the retrieval targets have been managed as attributes of the classification tree, so that the classification tree must be updated whenever a URL is added/deleted.
(5) The classification is different depending on the URL retrieval systems even in the case of retrieving the same URL.
It is therefore an object of the present invention to provide an information retrieval scheme capable of realizing an information retrieval in which the information sources and the classification tree are defined separably, so that the construction of the information retrieval system using classification tree becomes easier, the reutilization and the sharing of a classification tree of information become possible, and the sharing of the information sources that are the retrieval targets becomes possible.
According to one aspect of the present invention there is provided an information retrieval apparatus using classification trees with respect to a plurality of information sources connected to a network, each classification tree having a hierarchical structure defined in terms of entries, the apparatus comprising: a class definition unit for managing classification tree class information for each classification tree class defined among entries constituting each classification tree, each classification tree class information indicating retrieval condition parameters for each classification tree class; and an information retrieval control unit for receiving from a user a retrieval request indicating a retrieval target entry that was obtained by the user by tracing the classification trees, generating retrieval commands with respect to selected information sources among said plurality of information sources by referring to each classification tree class information corresponding to the retrieval target entry that is managed by the class definition unit, obtaining a retrieval result of a retrieval with respect to the selected information sources using the retrieval commands, and returning the retrieval result to the user.
According to another aspect of the present invention there is provided a method of information retrieval using classification trees with respect to a plurality of information sources connected to a network, each classification tree having a hierarchical structure defined in terms of entries, the method comprising the step of: managing classification tree class information for each classification tree class defined among entries constituting each classification tree, each classification tree class information indicating retrieval condition parameters for each classification tree class; and controlling an information retrieval by receiving from a user a retrieval request indicating a retrieval target entry that was obtained by the user by tracing the classification trees, generating retrieval commands with respect to selected information sources among said plurality of information sources by referring to each classification tree class information corresponding to the retrieval target entry that is managed by the managing step, obtaining a retrieval result of a retrieval with respect to the selected information sources using the retrieval commands, and returning the retrieval result to the user.
According to another aspect of the present invention there is provided a computer usable medium having computer readable program code means embodied therein for causing a computer to function as an information retrieval apparatus using classification trees with respect to a plurality of information sources connected to a network, each classification tree having a hierarchical structure defined in terms of entries, the computer readable program code means includes: first computer readable program code means for causing said computer to manage classification tree class information for each classification tree class defined among entries constituting each classification tree, each classification tree class information indicating retrieval condition parameters for each classification tree class; and second computer readable program code means for causing said computer to control an information retrieval by receiving from a user a retrieval request indicating a retrieval target entry that was obtained by the user by tracing the classification trees, generating retrieval commands with respect to selected information sources among said plurality of information sources by referring to each classification tree class information corresponding to the retrieval target entry that is managed by the first computer readable program code means, obtaining a retrieval result of a retrieval with respect to the selected information sources using the retrieval commands, and returning the retrieval result to the user.